This invention relates to a fuel filter positioned inside the tank containing fuel, such as for heating a building.
The typical commercially available fuel tank filter is located outside the tank and is essentially a small overflow filter to trap large particulate. The supply line extending an opening positioned above the bottom of the tank is threaded into a duplex bushing having two holes with standard 3/8 flare fittings. The supply line extends from the bushing to the small overflow filter and then to the burner. A return line provides a pressure release that extends from the burner back to the duplex bushing and opens into the interior of the tank. Particularly in above ground tanks, water condensation causes a substantial water collection at the bottom of the tank with the fuel floating on top. The height of that water can sometimes reach three to four inches inside the tank. Sooner or later, the water level will reach the opening at the bottom of the supply line and draw water into the system and into the small overflow filter. For installations at moderate climates with an outside tank, a year hardly ever goes by without at least one maintenance call to clean out the filter which is essentially removing the ice which has clogged the filter and forced shut down of the heating system. Even in buried tanks, water collects in the filter and is ultimately drawn into the burner with substantial corrosive and damaging effects. No filter systems have been offered to satisfy and alleviate these problems. Filter systems are described in U.S. Pat. Nos. 2,547,857 to W. S. Cook, 2,795,332 to R. A. Burla, 2,846,074 to A. D. Brundage, 2,946,449 to E. C. Shaw, and 3,023,905 to J. A. McDougal et al. None of the above devices satisfy the above needs nor attain the objects herein below.